@Deivid Herley
Azure File Sync is designed to work exclusively with Azure Files and does not connect to Blob Storage. I am unsure of your exact use-case but perhaps consider using something like azcopy sync to sync from your local system to your blob container. You could have this setup to run frequently on a schedule or trigged from your application.
Azure Storage offers built in redundancy options so it should not be necessary to manually make two copies of your blob. The lowest redundancy level is, Locally redundant storage (LRS), LRS copies your data synchronously three times within a single physical location in the primary region. You can view the various redundancy options here.
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